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HER2 Test Reclassification at KTPH

Name and Constituency of Member of Parliament
Dr Lim Wee Kiak, MP for Sembawang GRC

Question No. 419

To ask the Minister for Health following the error in the Khoo Teck Puat Hospital laboratory test for cancer patients (a) how many patients suffered side effects arising from being given the wrong treatment; (b) how many were treated at private hospitals versus Government hospitals; and (c) what is the average cost of medication incurred by all these patients

Name and Constituency of Member of Parliament
Ms Joan Pereira, MP for Tanjong Pagar GRC

Question No. 425

To ask the Minister for Health with regard to the case of breast cancer patients at Khoo Teck Puat Hospital who may have received unnecessary treatment since 2012 due to inaccurate test results (a) what are the key revelations from the review of the process; (b) what measures have been implemented to prevent similar incidents; and (c) whether there have been cases of patients suffering from detrimental effects.

Name and Constituency of Member of Parliament
Dr Tan Wu Meng, MP for Jurong GRC

Question No. 428

To ask the Minister for Health with regard to cancers inaccurately classified HER2-positive by Khoo Teck Puat Hospital laboratory (a) how many patients (i) received unnecessary treatment and (ii) suffered significant or long-term side effects thereby; (b) what is the ensuing cost to affected patients; (c) what is being done to help these patients; and (d) what measures are taken to ensure fidelity of laboratory tests.

Name and Constituency of Member of Parliament
Miss Cheryl Chan Wei Ling, MP for East Coast GRC

Question No. 451

To ask the Minister for Health with regard to the incident at Khoo Teck Puat Hospital where breast cancer patients received unnecessary treatment since 2012 (a) why did subsequent follow-up checks on the patients over the years not pick up any misdiagnosis from the earlier test; and (b) whether there are regular audits of hospitals and medical clinics on laboratory protocols to identify lapses.

Name and Constituency of Member of Parliament
Ms Hazel Poa, Non-Constituency MP

Question No. 457

To ask the Minister for Health what are the reasons for the wrong test results for cancer patients at Khoo Teck Puat Hospital and what measures will be put in place to ensure that such errors do not occur again. 


On 19 November 2020, Khoo Teck Puat Hospital (KTPH) was informed by its Laboratory that its immunohistochemistry (IHC) tests for Human Epidermal Growth Factor Receptor 2 (HER2) were producing higher-than-expected rates of positive results for breast cancer patients.  Preliminary investigations by the Laboratory suggested that some of the HER2 results may be inaccurate.  

Following the incident, the Ministry of Health has been working closely with KTPH to ensure that the affected patients are provided with adequate support. KTPH has sent the samples of all patients, who have been tested HER2 positive since 2012, when HER2 testing first started in KTPH, to external laboratories for re-testing to determine how many have received inaccurate results. Preliminary investigations by the KTPH laboratory suggest that the inaccurate results could be due to a suboptimal staining process. The KTPH laboratory has since stopped in-house testing for HER2. The Ministry of Health has also issued an alert to our other public healthcare institutions to conduct a quick review of their laboratory-developed IHC tests to ensure that positivity rates are within the acceptable range. Thus far, we have not received any reports of similar risks from other healthcare institutions. 

KTPH’s Department of Laboratory Medicine is subject to regular inspection by MOH as part of the regulatory processes under the Private Hospitals and Medical Clinics (PHMC) Act to ensure that its laboratory facilities, systems and processes are in place to meet patient and personnel safety standards. In addition, the laboratory is accredited by the College of American Pathologists (CAP), where the last biennial inspections by peers were conducted in 2019. 

As at 23 December 2020, 200 patients have been reclassified from HER2 positive to HER2 negative. Of these, 8 patients were treated at private hospitals and 192 patients at Government hospitals. 8 patients are still pending retests.  Joint care teams have been formed, comprising KTPH surgeons, histopathologists, and the treating oncologists, to review the individual care plans for these affected patients, based on the change in their HER2 status. 

KTPH and the treating oncologists are in the process of actively reaching out to these patients to conduct open disclosure and to assess these patients for any potential side effects due to unnecessary treatment. The more common side-effects include diarrhoea, chills and fatigue. These are usually short lasting. About 3 to 4 percent of those who underwent HER2-directed treatment (e.g. using Herceptin) may also experience heart problems. KTPH is also reviewing the bills of these affected patients. The portion of the bills which arose from the unnecessary treatment will be fully refunded. KTPH is also ready to provide any clinical and financial support to the affected patients including on-going or follow-up treatment, if any, which may be needed as a result of over-treatment.

The National Healthcare Group has convened an independent review committee, comprising external experts from multiple relevant disciplines in the healthcare industry. The objective is to conduct a thorough evaluation of the incident, to understand better the lapses that have occurred and recommend appropriate measures to improve the process. This ensures that any system gaps are identified and addressed swiftly to prevent recurrence of similar incidents. 

The committee’s investigations are ongoing right now and more time would be required to ensure a thorough review. NHG will provide an update when more information is available and these findings will be shared with the other healthcare institutions for improvement.

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